Genetic tendencies unveiled

Curled inside every cell in your body is a blueprint for building and operating a human being. Scientists first sequenced the entire human genome 10 years ago, but they’re still unravelling the secrets of how DNA influences our health and behaviour. Researchers have been studying specific genes’ effects on our wellbeing to use genetic idiosyncrasies to customise medical care. Here are some key discoveries that could lead to better health. – Sarah Fecht

Gene: MAOA

What it does: Happiness can come from a lot of places, but a study last year by researchers at various institutions, including the National Institutes of Health in the US, suggests that at least part of it comes from the gene MAOA, which sets out the blueprint – the scientific term is “codes” – for an enyzme that breaks down serotonin and dopamine, two behaviour- and mood-modifying neurotransmitters.

Implications: The scientists linked the low-activity variant of MAOA to happiness in women but not in men. Their findings, which reveal “the first happiness gene for women”, could help explain happiness variation across genders and promote more attention to genetics’ link to mood.

Gene: WNT16

What it does: In 2012, more than 50 researchers in Europe, North America and Australia found a strong connection between this gene and both bone density and cortical bone thickness. The higher both of these factors are, the lower the risk of fracture.

Implications: By stimulating the pathways WNT16 affects, doctors could strengthen bones. Doctors might also look for a variant of the gene, which disrupts signalling pathways, to identify weaker-boned patients whose risk of broken bones could be decreased by preventative medication.

Gene: MDR1

What it does: A transplanted kidney with MDR1, a multidrug resistance gene, has a 69 per cent greater risk of long-term failure. Transplant patients must take medicine to prevent organ rejection, but that medicine can become toxic if too much builds up. Donor kidneys with this form of MDR1 can’t effectively filter toxic substances – including medicine – which leads to failure.

Implications: If researchers can firm up the link between the genevariant and transplant rejection, surgeons could test donor kidneys tomake sure they don’t have the genetic variant.

Gene: DOK7

What it does: Researchers in Barcelona showed that changes in the expression of the DOK7 gene can give one identical twin a higher risk of breast cancer. They are able to detect the risk years before a clinical diagnosis of cancer would be possible

Implications: If monozygotic twins have the same genome, logic says that genetics-based diseases would show up at the same time. But that’s not always the case. Part of the explanation may lie in epigenetic marks, the chemical signals that turn genes on and off. Researchers will now study the exact effects of the gene, hoping to create targeted, gene-based treatments.